Stove or furnace.



Patented Dec. l2, I899." s. A. McKENZIE & c. w. nous.

STOVE 0R FURNACE.

(Application filed Feb. 20, 1899.)

(No Model.)

' 5 moan Mom 1 A. M. K @513 Mahler/14mg W. HM L.

PATENT rrr GEORGE A. MCKENZIE AND CHARLES WM. I-IOUGI-I, OF VEST BAYCITY,

MICHIGAN.

STOVE OR FURNACE.

SPECIFICATION forming part of Letters Patent N0. 638,934, dated December12, 1899.

Application filed February 20, 1899. Serial No. 706,175. (No model.)

To all whom, it may concern:

Be it known that we, GEORGE A. lVICKENZIE and CHARLES WM. HoUeH,citizens of the United States, residing at West Bay City, in the countyof Bay and State of M ichigan,have invented certain new and usefulImprovements in Stoves or Furnaces; and we do hereby declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains tomake and use the same.

This invention relates to stoves, and more particularly to stoves usingthe cheaper grades of coal, such as bituminous slack, for fuel.

The improvement consists in certain arrangements of the parts of thefire-box, distribution of the air-supply to the fire, and means forinducing currents of heated air through the stove and room, all as morefully set forth hereinafter.

The objects of the invention are, first, to produce a soft-coal-burningstove, to which the coal is supplied from above and burned on a gratebelow, the draft being downward through the fire-bed and grate andaround the base of the stove; second, to produce a fire-bed in the shapeof an annular ring of burning coal, to which air may be supplied fromwithin the ring or without, or both; third, to produce a stove forburning soft coal having means for regulating the height at which thecoal is coked, thus increasing or decreasing the depth of the fire-bed,and, fourth, to provide means for producing a circulation of air throughthe center of the stove and through the room. The means by which weaccomplish these results is plainly shown in the accompanying drawings,throughout the several views of which similar figures of referencedesignate similar parts and devices.

Figure 1 is a central vertical section of a stove embodying ourimprovements, the section being taken parallel to the front of thestove. Fig. 2 is a partial horizontal section of the stove, taken on theline m a: of Fig. 1. Fig. 3 is a central vertical section of the stove,the section being taken parallel to the sides of the stove. Fig. 4 is across-sectional detail of an inner fire-pot ring.

As is clearly shown in the drawings, the

stove consists of a rectangular base surmounted by a cylindrical shellcontaining the fire-box and magazine.

The fire-box 1 consists of a cylindrical shell of cast-iron or othersuitable material placed above the grate 2, as is usual in stoves ofthis class, and supported by lugs 1 on the outer shell of the stove.Around the fire-box are openings l for the intake of air. These openingsare preferably provided by casting the fire-box in two parts, the upperpart 1 resting upon the lower and separated from it by projections, thespaces between which form the openings 1", as shown in Figs. 1 and 3.

The coal is supplied to the fire-box through a funnel-shaped chute 3,supported around its circumference by the fire-box and having a centralopening of smaller diameter than the fire-box.

Extending vertically through the grate and fire-box and concentric withthe latter is a hollow cylindrical tube or pipe 4, which forms anessential feature of our invention. This pipe 4 is preferably built upof a number of annular rings of cast-iron, each ring having its uppersurface beveled downwardly and outwardly, as at m, Fig. 4, and its lowersurface parallel with the upper surface. the upper beveled surface ofeach ring are a number of projections or distance-pieces n. It isapparent that-when the several rings are built up they form a tube orpipe 4, having at various heights downwardly-directed openings or twyersconnecting the interior of the tube with the fire-box. A vertical pipe 5is attached at its lower end by screwthreads or otherwise to the topring 4 of the tube 4 and extends through the magazine to the air. Aprotecting-covering of fire-brick 5 may be applied to the pipe 5. Asmaller pipe 6 extends through the tube 4 and communicates with the pipe5 by screwing into the lower end of the ring 4, which thus forms areducer for the pipes 5 and 6, as shown in Fig. 1. A tapered annularspace 7 is left between the pipe 6 and the tube 4, through which air mayflow to the fire-box. Air is supplied to the space 7 and thence to thefirebox by a pipe 8, which communicates with the air through a chamber8.

Goal is introduced into the magazine through a door 9, the operation ofwhich will be more fully described hereinafter. The ashes drop throughthe grate Z and a suitable chute 10 into the ash-box l1.

The lower end of the pipe 6 communicates with an opening 6 cored in thebottom section of the tube 4, which in turn opens to the air near thefloor through a pipe 6".

The operation of the stove is as follows: Coal introduced into themagazine through the door 9 feeds through the chute 3 to the fire-box l,where it is coked by the combined heat of the fire beneath and theadmixture of air through the openings 1 and the draftdoors 12, which aremounted in the outer shell 13, surrounding the fire-box, as shown inFigs. 1 and 2. The combined air and volatile gases given off by the coalin coking pass downwardly through the fire bed and grate 2 and into thespace 14:, which surrounds the ash-pan 11. Thence they pass back throughthe passage 14 to the chimney. Meanwhile air is admitted to the chamber8 through a draft-door 8 in the side of the stove, passes through thepipe 8 into the space 7, and thence is drawn through the twyers into thecoalbed surrounding the tube 4. It is thus seen that an annular ring ofcoke is formed in the fire-box and is subjected to the combined draftsfrom the openings 1 around the outside aud the twyers of tube 4 aroundthe inside. The effect of these combined drafts is to entirely consumethe combustible matter of the coal and to. produce a smokeless fire witheven the cheapest grades of slack coal.

When the inner tube 4 is omitted and the outer draft-openings 1 aloneare used, it is found in practice that the coal nearest the openingsburns first, and an easy passage for the air being then established nearthe firebox shell the coal in the center is not readily consumed and aninverted cone of unconsumed coal remains embedded in the ashes after thefire has burned out, whereas upon inserting the tube 4 into the fire-boxand by it supplying air to the inside of the fire-bed combustion isgreatly facilitated, and on allowing the fire to burn out no unconsumedcoal remains in the fire-box.

In practice we prefer to provide doors or openings below the chute 3, as12, Fig. 1, through which the coke may be broken by a poker, if desired.Similar doors 12 are provided above the level of the grate for pokingthe ashes and removing any clinkers that may accumulate in themagazine.-

By passing the pipe 6 through the tube 45 and connecting 6 to the pipe 5we are enabled to produce a current of air from near the floor throughthe heated parts of the stove and into the room above the stove, thusincreasing the circ ulation of heated air throughout the room andefficiently warming it.

The door 9, through which coal is introduced into the magazine, ispreferably made to conform in shape to. the shell of the stove whenclosed, and being hinged at its lower end by bolts 9, attached to thestove, it rests on the chute 9 when open, as is plainly shown in Fig. 1.Two sides or wings 9 project inwardly from the door 9 and, with thedoor, form a chute through which the coal passes.

A lug 9 projecting upwardly from the edge of one of the wings isarranged to engage the under surface of a trap-door 15 in themagazine-top 16 and to raise this door as the door 9 opens. The trapdoor 15 is preferably hinged to the stove at 15, as shown in Fig. 1.

Above the magazine-top 16 is a second cover 17,'and the space betweenthe two communicates with the chimney-pipe through a pipe 18. Gas thatmay have accumulated in the top of the magazine will pass through thetrap-door opening and into the chimney as soon as the trap-door israised by the lug 9 when the door 9 is opened. By this means we preventgas escaping into the room when coal is put into the stove. In practicewe prefer to surmount the chute 9 with a bellmouth 19 and a cover 19.

Although the normal draft of the fire is downward through the fire-boxaround the base and into the stovepipe, it is sometimes desirable instarting the fire to use direct draft. We accomplish this object byproviding a pipe 20, Fig. 3, connecting the space around themagazine-openings 1 with the stovepipe and placing a damper 20, asshown, so as to allow the gases to pass directly from the fire-box intothe stovepipe when the damper is horizontal or to cause them tocirculate around the base when the damper is vertical.

In order to prevent overheating the floor by the hot gases circulatingthrough the base of the stove, we provide below the stove-bottom asecond bottom 21 for containing nonconducting material or for allowingthe free circulation of air between the two bottoms, if desired.

Although we have shown and described our improvement as applied to avertical heating-stove, we wish it understood that the im-' provedmagazine construction is equally ap-' plicable to cooking-stoves and tofurnaces. In applying to a range or furnace the Ventilating-pipes 6 and5 may be omitted, as the office of these pipes is mainly to increase thecirculation of heated air in the roomin which the fire is placed.

What we claim as our invention, and desire to secure by Letters Patent,is as follows:

1. In a stove, a fire-box consisting of a grate in combination with afire-box shell having downwardly and inwardly directed openings aroundits periphery, the inner ends of said openings being flush with theinner surface of the fire-box shell; a tube within the firebox, saidtube having downwardly and outwardly directed openings around itsperiphcry; a pipe for admitting air to the tube and having a draft-doorfor regulating the airsupply; a second pipe extending vertically throughthe tube, the coal-magazine and the fire-box, and open to the air atboth ends, said pipe having means for regulating the passage of airtherethrough, substantially as described.

2. In a downdraft magazine stove or furnace the combination with anouter fire-box shell having air-passages around its circumferenceadapted to discharge air into the firebox from the space surrounding thefire-box; of a tube extendingly upwardly within the fire-box and havingseries of air passages around its circumference adapted to discharge airoutwardly; a pipe connecting the tube with the outer air and havingmeans for regu lating the air-supply to the interior of the tube; saidfire-box shell and tube comprising means whereby air is drawn by thenatural draft of the fire into the fire-box and delivered against theannular fire-bed both from within and from without, substantially asdescribed and for the purposes set forth.

3. The combination in a downdraft-stove, of an outer fire-box shellbuilt up of superimposed cylinders having air passages between thecylinders, an inner fire-box tube built up of superimposed rings havingairpassages between the rings, a pipe for admitting air to the tube, asecond pipe extending centrally through the tube and fire-box and opento the air at both ends, substantially as and for the purpose described.

4. A downdraft magazine stove or furnace comprising an outer fire -boxshell having openings through its circumference for entrance of air fromwithout; of an upwardly-ex tending tube within the fire-box havingairpassages adapted to discharge air outwardly; a pipe leading from thebottom of said tube to the outer air and having a damper for regu latingthe flow of air therethrough; said firebox and tube having substantiallyvertical walls without lateral projections, thus pre venting fuel fromclinging to the Walls, all arranged substantially as described and forthe purposes set forth.

In testimony whereof we affix our signa= tures in presence of twowitnesses.

GEORGE A. MCKENZIE. CHARLES WM. HOUGI-I.

Witnesses:

DAVID Ln FAvoUR, J OHN J. RownLL.

